Without a top draw on Saturday night’s “Heavy Artillery” card, Strikeforce failed to break the 500,000 viewer mark they attained with shows featuring Gina Carano and Herschel Walker. According to MMA Junkie, an average of 308,000 viewers tuned in to see the event featuring Alistair Overeem’s return to the US.

This past weekend’s “Strikeforce St. Louis: Heavy Artillery” event, which featured the long-awaited return of heavyweight champion Alistair Overeem to the U.S., drew an average of 308,000 viewers on Showtime.

While the premium cable network has yet to officially announce the ratings, MMAjunkie.com (www.mmajunkie.com) confirmed the figures with industry sources.

Compared to Strikeforce’s most-recent Showtime-broadcast event, January’s “Strikeforce: Miami,” the numbers were down 40.43 percent from the 517,000 viewers that tuned in to see a pair of title wins by Nick Diaz and Cristiane “Cyborg” Santos along with performances by Bobby Lashley and Herschel Walker.

The numbers were however on par with Strikeforce’s other Showtime events, such as Strikeforce “Evolution” (341,000) and Strikeforce “Lawler vs. Shields” (275,000). It seems without a major star, Strikeforce does somewhere around 250k – 350k average viewers, and 500k-600k with one. Strikeforce runs two more Showtime events in June with their Los Angeles card headlined by Robbie Lawler vs. Babalu Sobral and their San Jose card headlined by Fedor Emelianenko vs. Fabricio Werdum. We’ll see if the trend continues then, but for now, I think the real story in these numbers is that Strikeforce/Showtime have failed to grow their fanbase in the first year of their partnership.

Meanwhile, the UFC’s counter-programming effort on Spike, “Ultimate Fights,” pulled an average of 894,000 viewers. However, it’s not an apples-to-apples comparison since Spike is available in roughly 86.6 million more households than Showtime is (98.6m-12m).

Image via Esther Lin for Showtime

Update: Heavy Artillery peaked during the main event with 448,000 viewers according to MMA Junkie’s sources.

While some MMA pundits have declared the figure a failure and a sign that Strikeforce’s deal with the premium cable channel may be in trouble, sources close to the partnership indicated to MMAjunkie.com (www.mmajunkie.com) that quite the opposite is true.

While quarter-hour figures, which often rise during mixed martial arts events, were not released, the sources indicated that the “Strikeforce St. Louis: Heavy Artillery” broadcast peaked during the main event of Alistair Overeem vs. Brett Rogers with 448,000 viewers.